Hi all,
I'm interested in giving the DirectLogic PLCs a try. I have read many good reviews about their reliability and affordability in this forum.
In my short life as a PLC programmer, I have only used the AB line: Microloix 1200 and 1500, and I'm currently working on my first project using a CompactLogix.
Could you give me advise on what would be the DirectLogic equivalents for those AB PLCs I mentioned above?
Regarding the pogramming tags, it seems that the DirectLogic software(Directsoft) does not offer UDT (user defined tags) as RSLogix 5000 does. Am I right?
I am willing to cut costs and try those PLCs that so many people praise, but I wouldn't like to miss anything relevant by not using Allen Bradley.

Nothing in the AutomationDirect/DirectLogic line compares to the Allen Bradley Control/Compact/Flex Logix line as far as tags and UDTs go.

The DirectLogic DL06 compares roughly to the Micrologix 1200. The power of the DirectLogic 205 family (especially with the DL260 CPU installed) compares favorably with the power of the Micrologix 1500.

None of the AutomationDirect line uses the Allen Bradley communication networks as masters. The I/O can be configured as Devicenet slaves but that's not really the point. Though they do have remote expansion capabilities it is via their own communication methods. MODBUS (serial) and MODBUS/TCP are the only non-AD communication protocols supported for communication to I/O.

I would recommend the AD line for single machines, not part of a tightly integrated line, especially if a plant already has AB as a standard.

But the prices are a whole other story.

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Controlling outputs is the PLC's way of getting its inputs to change.

I agree with Bernie's cross reference between models. The 205 does match the capabilities of the CompactLogix series in my opinion.

RSLogix 5000 is better in many areas than DirectSoft, including the tag based programming and UDT capabilities. I think DirectSoft is better than RSLogix 500, which some of the platforms you mention use. It is more intuitive and has a shorter learning curve in my opinion.

I disagree about networking. We have a lot of systems using multiple AutomationDirect PLCs on serial and radio links. WE have many networks using Allen Bradley as well. The protocol is different, but I don't believe there is any significant advantage of one over the other there. I think it is easier to set up AutomationDirect networks, they are less timing sensitive and play better with other vendors equipment using ModBus. Message block implementation in RSLogix 500 is clumsier than DirectSoft. User Producer data can be simpler in RSLogix 5000 but there are restrictions.

All other things being equal I prefer AutomationDirect.com systems as a better overall value. Part of that is better price, part of it is better service and factory tech support. My local AB distributor offers great tech support, but not all do.

It's been 10 years since I've admittedly used DL processors. At the time, it was there top of the line 405 (I think)? Has the implementation of Real, Integers, BCD, Binary changed significantly since then? It was a royal pain in the arse at that time to do math between number types. Lots of conversions and lots of push/pop from the stack. Also, the Modbus comms w/ Wonderware weren't trivial either. There was no direct association between the item name in WW and the DL address.

The reason that we used the DL then was the need for 8 high speed counters on one machine. Using the SLC 1747-HSCE was an order of 10 times the cost of using one of DL's high speed 8 channel magnetic input modules. But the math made it suckeeee.

4 years ago i switched a slc 5/04 with 36i/36o to automation direct. Initally I used a 205 with the 260 processor. After I changed the program over to AD it worked exactly like the slc 5/04.. 1 year ago I swithced and used 2 dl-06 using modbus with a flexible cable to communicate with a robotic gantry. After 1 year of use there is no noticable difference from the original slc 5/04 and the 2 dl-o6 units. Using modbus I run no wires just plug in the comm cable and go...saves many many hours and have never had the modbus com fail. I use do-dcm in 1 unit and in the slave I have a scrolling markee. Never any failures or glitches.

I found the math capabilities of the AD line familiar since I had programmed microprocessors where preliminary arguments to a math operation were loaded into an accumulator and the results stayed in the accumulator until sent elsewhere.

The new IBoxes didn't add any capability to the line, just made it easier to formulate a more involved math sequence. It still uses the same math instructions. It just has to do the thinking about order for you. I prefer rolling my own and being totally in control.

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Controlling outputs is the PLC's way of getting its inputs to change.